1. Field of the Invention
The invention relates to locks for locking a pair of adjacent, pivotally mounted doors that close at a common line. More particularly, the invention relates to a locking system for locking the rear doors of the trailer of a tractor-trailer rig wherein a portion of the locking system may be utilized to cover the king pin or coupling pin of the trailer.
2. Description of the Prior Art
It is well known that the pivotally mounted rear doors of the trailer of a tractor-trailer rig must be securely locked in order to secure the cargo during transfer operations and to prevent cargo theft when the trailer is unattended. Conventional door locks have proven ineffective, especially against theft prevention. Thus, there is a need for a reliable, heavy-duty door lock particularly suited for use on the rear doors of trailers.
It is also well known that the trailers of tractor-trailer rigs are often parked in isolated spots or left unattended so that they are susceptible to being hijacked by unauthorized persons. It has been proposed to provide a rugged, heavy-duty cover to fit over the king pin or coupling pin of a trailer to prevent hijacking.
No known locking device is capable of serving as either a cover for the trailer king pin or, in an alternate mode, as a locking device in a trailer door lock.